The invention relates to a device for determining the required length of a middle ear implant with a disk-shaped base part to which prosthesis mockups of various lengths are attached, which, after being detached from the base part, can be inserted by means of an applicator into the middle ear of a patient during an operation for length determination purposes.
A device of this kind is known from EP 1 449 499 A2.
The device serves as an accessory for adjusting the length of middle ear implants, in particular partial or total prostheses, during an operation on the human ear. In this case, entirely or partially missing ossicles of the human middle ear, which are supposed to transmit the sound from the eardrum to the stapes or stapedial footplate, are replaced by means of a corresponding middle ear prosthesis to be individually adapted to the specific proportions of the particular patient. Since the dimensions and geometries are different in the ear of each person, a total reconstruction requires the distance to be precisely determined between the eardrum and the stapedial footplate and a partial reconstruction requires the distance to be precisely determined between the eardrum and the stapedial head before a corresponding prosthesis can be inserted. To this end, prosthesis mockups of various sizes, which have typically the shape and form of a normal prosthesis are inserted into the middle ear of the patient during the operation in order to make a precise length determination.
Since prosthesis mockups of this kind are naturally very small, they are quite difficult and complex to manipulate, particularly in terms of their cleaning and sterilization. This is why the device described in the above-mentioned EP 1 449 499 A2 was developed, which supplies the prosthesis mockups in an easy-to-manipulate form on the circumference of a base part, attached by means of bridge pieces. After they are detached from the base part, the mockups can be inserted into the middle ear of the patient by means of a suitable applicator for purposes of length determination.